Process of separating solids from liquids.



-No. 885,451. PATENTED APR. 21, 1908.

E. W. DEMING.

PROCESS OF SEPARATING SOLIDS FROM LIQUIDS.

APPLIGATION FILED MAY 20, 1907.

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EUGENE W. DEMING, OF NEW YORK, N. Y.

PROGESS OF SEPABATING SOLIDS FROM LIQUIDS.

Specification of Letters Patent.

Patented April 21, 1908.

Application filed May 20, 1.907. Serial No. 374,673.

an absorber or cooler, and an open settling tank designed to operate under continuous flow, suitable conduits being provided whereby the liquid to be treated is led through the several devices is succession. As therein described the cold liquidfirst enters the absorber,-, passing thence through the digester in which it is highly heated, preferably to a temperature exceeding its atmospheric boiling point;

the superheated liquid from the di ester then reenters the absorber and is cooler? thereinto a temperature not exceeding its atmospheric boiling point, the cooling being effected by transfer of heat to the cold liquid passing through the absorber on its way to the digester. The partially cooled li uid is then led to the continuous settling ta where the suspended impurities are separated.

My present invention is a process of treat- .ing li uids carrying solids in suspension, and

speci really saccharine solutions, the object of the invention being to separate the solidsin a more economical and expeditious manner than has heretofore been possible, and in the case of saccharine and similar solutions ossibility of deterioration of the solutions y fermentation or otherwise.

The invention is based upon the observation that while the specific gravity of liquids and solutions is reduced at high temperatures, the s ecific gravity of suspended solids or coagu ated impurities is substantially unaffected, from which it follows that such solids or impurities will separate with comparative rapidity and completeness from ighly heated liquids. To secure this a closed receptacle or separator is used. A

further advanta e in maintaining the liquid under pressure uring the separation lies in,

the fact which I have observed that under these conditions the se aration of gas bubbles, which under or inary circumstances tend. to to the solid particles and to ,ings showing. a digester and absor maintain them in suspension, is largely avoided. p

For full understanding of myinvention. reference is made to the accompan 'ing drawber of conventional formin elevation, and a suitable se arator or settling tank in. vertical section. {eferring to the drawings, 1 represents a 'digester which may conveniently be of the type shown in my Patent Number 531,460 above referred to; 2 is an absorber of the general type therein described, its essential eature being the provision of two independent passages for liquid whereby a transfer of heat may beeifected between two bodies or. between two portions of the same body of liquid. The construction of these devices is well understood by those skilled in the art and they need not be further described herein.

3 represents a closed separating tank comrisin in the articular form shown a c lindrical sheet-metal body 4 to which is secured a conical bottom 5 having an out-let 6 for the precipitate; the bottom is suitably reinforced as shown at 7, 8, and appropriate supporting lugs or brackets 9 are provided. The tank is provided with a liquid-tight cover 10, of sheet-metal, which may be inwardly or outwardly arched to withstand high internal pressures of liquid. 11 is an interior pipe or partial partition which is secured. to the cover 10 and may be entirely supported thereby, or may be partially supported from the body of the tank as by brackets 32. The purpose of this pipe or partition, hereinafter designated the uptake is to provide a tor tuous passage for theliquid within the tank and to avoid convection currents, the entering liquid carrying solid matter in suspension being introduced through pi cs 12, .12 and flowing downwardly througli the annular passage 13 between the uptake 1] and the cylindrical body' 3 of the tank; the liquid flows around the base of the uptake 11, upwardly through the same, and escapes from the tank at 14, passing thence to the ab sorber as hereinafter described. The uptake is preferably of substantially conical form,

the base being wider than the top as herein shown and as described in my prior patent Number 566,726, patented August 25, 1896, in order that the upward rate of movement of li( uid in the lower portion of the tank may be re atively slow and the solids effectively separated. i 4

When operating to separate the solid mat-' ters' or impurities under high pressure and temperature, the course of the liquid through the apparatus is as indicated by the arrows upon t e ure and is as follows: The liquid enters the system at 15 and passes by pipe 18 to the upper portion of the absorber 2, which.

' it traverses, flowing thence by pipes 17 and T8 to the digester 1, wherein it is heated, preferablybut not necessarily to a temperature exceeding its atmospheric boiling point. The heated liquid then passes directly by pipes 19, 20 to the inlets 12, 12 of the settling tank 3, thetemperature and pressure of the liquid being substantially maintained during its passage through the tank and during the separation or precipitation of'the solids or provided in the piping system as will-be understood without particular description. 1 prefer to so arrange the piping systemthat either the absorber or the separating tank may be temporarily or permanently disconnected for convenience in repairing or'for other reasons which may render it desirable.

, Thus by means of the inlet valve 24 the inflowing liquid may be directed by pipe 25 to the digester' l'without passing through the absorber, and similarly the clear liquid flowing from the tank-3 may be conducted by pipe 26 directly to the evaporator without further cooling, the absorber being then entirely disconnected from the system. Or the evaporating tank may be disconnected bycloslng the valve in pipe 20 and opening the valve in pipe 27, in which case the heated liquid from the digester passes directly through the absorber. The recise manner in which the apparatus is user will depend to some extent upon the degree to which the liquid is heated in the digester 1 ifthe liquid is not highly heated therein the importance of the subsequent abstraction of heat in the absorber will be correspondingly lessened.

The discharge 6 for the solid matter may be provided with three branches as shown, which are connected respectively with the filter presses or bags, the scum tanks, and the suction of the filter press pump, thus permitting a considerable range for the disposal of the precipitate' The filter press being connected directly with the tank may be operated exclusively by the pressure therein, thus avoiding the use of pumps or scum tanks, the necesslty of adding water to the scums, the addition of lime to the scums. the necessity of heating the same and the labor incident to the operation of scum tanks.

For the removal of any scum which may accumulate in the region of the discharge of the tank 4 I prefer to provide a device comprising a concave casting -or basin 29 arranged within the uptake 11 and carriedby a pipe 30 which is vertically adjustable in a stuffing-box and delivers to the juice or gravity filters or 'to bag filters. By permitting the juice to discharge through )ipe 30, the scum overflows the sides of the asin 29 and passes thence from the tank. The basin may begradually lowered until the juice discharged is free from scum, when the delivery through the regular channels may be resumed.

In cases where it is practicable to filter the entire body of juice I may convey the juice from the heater througha closed tank, column or the like of sufficient size to afiord the time and conditions re uisite for flocculation, and thence direct y to the filterpresses. The temperature in this case need not necessarily exceed the boiling oint'under atmospheric pressure, but shou d be sufficiently high to secure effective'defecation and to insure ready filtration. Ifdesired the juicesimay becooled either before or after filtration by transferring heat therefrom to the inflowing juice.

When treating saccharine or other solu-' tions in which a flocculation due to the temperature occurs, it is found'that in practice the impurities do not separate in flocculent form before the liquid reaches (the tank 4. This is highly advantageous for. the reason that such solutions show no tendency to clog or scale the pipes which they traverse on their Way to the tank. It is to be understood that little or no settling of the solids in the usual meaning of this term occurs in the separating tank; the solids are in fact conveyed to a point near the bottom of the tank by the inowing liquid, where, owing to their higher s ecific gravity, they remain until withrawn. The construction of the tank and the relative position of its inlet and discharge openings, which are so situated that the hottest li uid is always in proximity to the outer wal s of the tank, are such as to avoid the production of convection currents or any disturbances of the separated matter. Obviously the apparatus may be operated intermittently inorder .to afford any desired period for the separation of the impurities in the tank 4.

As applied to the treatment of, saccharine solutions, as uices from sugar cane, the juice is first treated with lime, or wlth lnne and sulfur dioxid, and is then conveyed through the pipes of the 'digester or heater at such rate as to prevent substantial separation or flocculation of the precipitate; thereafter the juice is brought to rest or to a condition of relatively slow movement, as in the course of 1 its passage through the tank 4, for such' period as may be required for the flocculation of the precipitate, being prefcn'ably maintained under pressure during eriod. y the most available means, which may involve both subsidence and filtration, and the clear juice is preferably cooled by transferthis The precipitate is then separated ring a portion o'l its heat to the infiowing juice, to the approximate temperature of the evaporators, in order that these may operate regularly and without objectionable variations ol temperature. The clarified juice is t hen led directly to the evaporators.

.l claim: 1. The

recess 01' separating solids from liquids which consists in heating a liquid carrying solids in suspension while preventing flocculation ot the solids, then permitting said solids to tlocculate and collecting them beneath a body of the heated liquid, and

finally cooling said liquid by transierringj heat therefrom to the inflowinp liquid.

2. The process of separating solids from liquids which consists in heating a liquid earrying solids in suspension while preventing flocculation of the solids, then permitting said solids to flocculate and collecting thenr beneath a body of the heated liquid, continuously withdrawing the clear liquid and the separate-j solids, and finally cooling said liquid by transferring heat therefro'in' to the rated solids, and finally cooling said liquid by transferring heat therefrom to the inl'lowing liquid.

5. The process of separating solids from liquids which consists in heating a liquid carrying solids in suspension while prevent ing flocculation of the solids, then permitting said solids to llooculate. and separating them from the heated liquid by filtration, substantially as described.

6. The process of treating saccharine solutions which consists in heating said soluilocculation of the solids, then permitting! said solids to l'locculate While retaining them under pressure and collecting them beneath a body of the heated liquid, and finally cool 1 ing said liquid by transferring heat therefrom T to the inflowing liquid.

3. The process o'l' separating solids from f liquids which consists in heatin rying solids in suspension WlUTQ a liquid carpreventing tions while preventing flocculation of solids carried thereby, then permitting said solids to llocculale, andscparating them from the heated liquid by filtration, substantially described.

In testimony whereof, I allix my signature in presence. oi two witnesses EUGENE W. DEMING. Witnesses V. Fowm-zu, K. T. RICHARD. 

